North America

Photo by: Flavijus Piliponis

North America, the world's third-largest continent, encompasses an
area of about 9,400,000 square miles (24,346,000 square kilometers). This
landmass is occupied by the present-day countries of Canada, the United
States, Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa
Rica, and Panama. Also included in the North American continent are
Greenland, an island landmass northeast of Canada, and the islands of the
Caribbean, many of which are independent republics.

North America is bounded on the north by the Arctic Ocean, on the west by
the Bering Sea and the Pacific Ocean, on the south by the South American
continent, and on the east by the Gulf of Mexico and Atlantic Ocean.

The North American continent contains almost every type of land-form
present on Earth: mountains, forests, plateaus, rivers, valleys, plains,
deserts, and tundra. It also features every type of climatic zone found

North America.
(Reproduced by permission of

The Gale Group

.)

on Earth, from polar conditions in Greenland to tropical rain forests in
the countries of Central America. Much of the continent, however, is
subject to a temperate climate, resulting in favorable farming and living
conditions.

The highest point on the continent is Mount McKinley in Alaska, standing
20,320 feet (6,194 meters) in height. Badwater, in the south-central part
of Death Valley in California, is the continent's lowest point, at
282 feet (86 meters) below sea level.

Coast of Lake Michigan at Indiana Dunes National Lakeshore, Indiana.
(Reproduced by permission of the

National Parks Service

.)

Rivers and lakes

The North American continent contains the world's greatest inland
waterway system. The Mississippi River rises in northern Minnesota and
flows 2,348 miles (3,778 kilometers) down the center of the United States
to the Gulf of Mexico. The Missouri River, formed by the junction of three
rivers in southern Montana, runs 2,466 miles (3,968 kilometers) before it
joins the Mississippi just north of St. Louis, Missouri. The Ohio River,
formed by the union of two rivers at Pittsburgh, Pennsylvania, flows 975
miles (1,569 kilometers) before emptying into the Mississippi at Cairo,
Illinois. The Mississippi, with all of its tributaries, drains 1,234,700
square miles (3,197,900 square kilometers) from all or part of 31 states
in the United States. From the provinces of Alberta and Saskatchewan in
Canada, the Mississippi drains about 13,000 square miles (33,670 square
kilometers).

Other chief rivers in North America include the Yukon (Alaska and Canada);
Mackenzie, Nelson, and Saskatchewan (Canada); Columbia and St. Lawrence
(Canada and U.S.); Colorado, Delaware, and Susquehanna (U.S.); and Rio
Grande (U.S. and Mexico).

North America contains more lakes than any other continent. Dominant lakes
include Great Bear, Great Slave, and Winnipeg (Canada); the Great Lakes
(Canada and U.S.); Great Salt Lake (U.S.); Chapala (Mexico); and Nicaragua
(Nicaragua). The Great Lakes, a chain of five lakes, are Superior,
Michigan, Huron, Erie, and Ontario. Superior, northernmost and westernmost
of the five, is the largest lake in North America and the largest body of
freshwater in the world. Stretching 350 miles (560 kilometers) long, the
lake covers about 31,820 square miles (82,410 square kilometers). It has a
maximum depth of 1,302 feet (397 meters).

Geographical regions

Geologists divide the North American continent into a number of
geographical regions. The five main regions are the Canadian Shield, the
Appalachian System, the Coastal Plain, the Central Lowlands, and the North
American Cordillera (pronounced kor-dee-YARE-ah; a complex group of
mountain ranges, systems, and chains).

Canadian Shield.
The Canadian Shield is a U-shaped plateau region of very old, very hard
rocks. It was the first part of North America to be elevated above sea
level, and became the central core around which geological forces built
the continent. It is sometimes called the Laurentian Plateau. It extends
north from the Great Lakes to the Arctic Ocean,
covering more than half of Canada and including Greenland. Hudson Bay and
Foxe Basin in Canada mark the center of the region, submerged by the
weight of glaciers of the most recent ice age some 11,000 years ago.
Mountains ranges ring the outer edges of this geological structure. In the
United States, the Adirondack Mountains and the Superior Highlands are
part of the Shield.

The southern part of the Canadian Shield is covered by rich forests, while
the northern part is tundra (rolling, treeless plains). The region is rich
in minerals, including cobalt, copper, gold, iron, nickel, uranium, and
zinc.

Appalachian System.
The Appalachian Mountains extend about 1,600 miles (2,570 kilometers)
southwest from Newfoundland to Alabama. They are a geologically old
mountain system. Formed over 300 million years ago, the Appalachians have
eroded greatly since then. Most of the system's ridges are 1,200 to
2,400 feet (360 to 730 meters) in height. Only a few peaks rise above
6,000 feet (1,800 meters). The system's highest peak, Mount
Mitchell, rises 6,684 feet (2,037 meters) above sea level.

The main ranges in the system are the White Mountains (New Hampshire),
Green Mountains (Vermont), Catskill Mountains (New York), Allegheny
Mountains (Pennsylvania), Great Smoky Mountains (North Carolina and
Tennessee), Blue Ridge Mountains (Pennsylvania to Georgia), and the
Cumberland Mountains (West Virginia to Alabama).

Much mineral wealth is found throughout the Appalachian System, including
coal, iron, lead, zinc, and bauxite. Other mineral resources such as
petroleum and natural gas are also prevalent.

Coastal Plain.
The Coastal Plain is a belt of lowlands that extends from southern New
England to Mexico's Yucatan Peninsula, flanking the Atlantic Ocean
and the Gulf of Mexico. This geological area was the last part added to
the North American continent. Much of the plain lies underwater along the
northern Atlantic Coast, forming rich fishing banks.

The southern portion of the plain, from Florida along the Gulf shore of
Louisiana and Texas into Mexico, holds large deposits of phosphate, salt,
and sulfur. Extensive oil and natural gas fields also line this area.

Central Lowlands.
The Central Lowlands extend down the center of the continent from the
Mackenzie Valley in the Northwest Territories in Canada to the Coastal
Plain in the Gulf of Mexico. These lowlands circle the Canadian Shield.
Included in this extensive region are the Great Plains in the west and the
lowlands of the Ohio-Great Lakes-Mississippi
area in the east. The great North American rivers are contained in this
region, making the surrounding soil fertile for farming. The
world's richest sources of coal, oil, and natural gas are also
found here.

North American Cordillera.
The North American Cordillera is a complex group of geologically young
mountains that extend along the western edge of the North American
continent. The eastern section of the Cordillera is marked by the Rocky
Mountains. They extend more than 3,000 miles (4,800 kilometers) from
northwest Alaska to central New Mexico. The highest peak in the Rockies is
Mount Elbert in Colorado at 14,431 feet (4,399 meters) in height. The
highest peak in the Canadian Rockies is Mount Robson in eastern British
Columbia, rising 12,972 feet (3,954 meters). The ridge of the Rocky
Mountains is known as the Continental Divide, the "backbone"
of the continent that separates the rivers draining to the Arctic and
Atlantic Oceans from those draining to the Pacific Ocean.

Snow-covered Mt. Sopris on the Crystal River near Aspen, Colorado.
(Reproduced by permission of

Photo Researchers, Inc.

)

The Rockies may be divided into three sections: northern, central, and
southern. The Northern Rockies, which rise to great elevations, begin in
northern Alaska and extend down into Montana. From here, the Central
Rockies extend down into Colorado. A high, vast plateau separates the
Central Rockies from the Southern Rockies. Known as the Wyoming Basin, it
varies in elevation from 7,000 to 8,000 feet (2,100 to 2,400 meters). The
Southern Rockies contain the highest peaks in the entire
system—many exceed 14,000 feet (4,300 meters) in height.

West of the Rockies lies a series of plateaus and basins. These include
the Yukon Plateau, the uplands in central British Columbia, the Snake
River Plain, the Great Basin, and the Colorado Plateau. The Great Basin,
an elevated region between the Wasatch and Sierra Nevada Mountains,
includes the Great Salt Lake, the Great Salt Lake and Mojave deserts, and
Death Valley.

The western edge of North America is marked by two mountain ranges: the
Cascade and Coast ranges. The Cascade Range extends about 700 miles (1,130
kilometers) from British Columbia through Washington and Oregon into
northeast California. Many of the range's peaks are volcanic in
origin. The highest peak is Mount Rainier in Washington, standing 14,410
feet (4,390 meters) in height. North of the Cascades are the Coast
Mountains, which extend about 1,000 miles (1,610 kilometers) north from
British Columbia into southeast Alaska. Here they are met by the Alaska
Range, which extends in a great arc through south-central Alaska. This
range features the highest peaks in North America, including Mount
McKinley.

South of the Cascades are the Sierra Nevada Mountains, extending about 400
miles (640 kilometers) through eastern California. The Sierras, noted
along with the Cascades for their beauty, contain Mount Whitney. At 14,494
feet (4,418 meters) tall, it is the highest peak in the contiguous United
States (the 48 connected states).

The Coast Ranges are a series of mountain ranges along North
America's Pacific coast. They extend from southeast Alaska to Baja
California. The ranges include the St. Elias Mountains (Alaska and
Canada); Olympic Mountains (Washington); Coast Ranges (Oregon); Klamath
Mountains, Coast Ranges, and Los Angeles Ranges (California); and the
Peninsular Range (Baja California). Peaks in the entire Coast Ranges
extend from 2,000 to 20,000 feet (610 to 6,100 meters) in height.

In Mexico, the chief mountain system is the Sierra Madre, composed of the
Sierra Madre Occidental, the Sierra Madre Oriental, and the Sierra Madre
del Sur. The Sierra Madre Occidental begins just south of the Rio Grande
River and runs about 700 miles (1,130 kilometers) parallel to the
Gulf of Mexico. The Occidental contains the highest peak in the Sierra
Madre system, Pico de Orizaba, which rises to 18,700 feet (5,700 meters).
Orizaba is also considered a part of the Cordillera de Anahuac, an
east-west running belt of lofty volcanoes just south of Mexico City. In
addition to Orizaba, this belt contains the volcanic peaks Popocatepetl
and Ixtacihuatl. The belt connects the Occidental range to the Sierra
Madre Oriental, which runs south from Arizona parallel to the Pacific
coast for about 1,000 miles (1,610 kilometers). The Sierra Madre del Sur
is a broken mass of uptilted mountains along the Pacific coast in southern
Mexico. It forms the natural harbor of Acapulco.